Never can a club song have been sung with such relief. The din coming from the cramped away dressing room beneath Wakefield's old clubhouse after this breathless cup tie signalled the release of the pressure that has piled up on the Wigan players in a run of six defeats in seven matches and continued to do so as they fell 22-6 behind yesterday.

"Wigan is synonymous with the Challenge Cup and with that comes pressure," admitted their coach Ian Millward, who was under more of it than anyone. "To come off at half-time after conceding 22 points - that's another real test of character and the players have been able to handle that really well."

They were helped considerably by Wakefield's inexplicable inability to perform in the second half, as they followed last Sunday's surrender of a 21-0 lead against Warrington by conceding 20 more points without reply. But the trigger for this week's transformation had been pulled just before half-time, when with Trinity leading 22-6 their Australian full-back Colum Halpenny cynically threw the ball away to buy his team-mates a few extra seconds to recover from a big defensive effort. He was spotted and penalised by the referee Karl Kirkpatrick and from the resulting Wigan pressure their veteran Australian forward Bryan Fletcher sent the young full-back Chris Ashton over for a try that Wayne Godwin converted to reduce the arrears to 10 points.

"I don't want to single anybody out but that one decision was the turning point of the game," Wakefield's coach Tony Smith said of Halpenny's aberration. "Obviously I let him know about it at half-time. Both teams were low on confidence but Wigan got a lot of confidence back from that."

They were level within five minutes of the restart, as first their captain Sean O'Loughlin shrugged off a weak attempted tackle by Jamie Field for the try his inspirational performance deserved, then Dennis Moran won the race to his own quick-thinking kick ahead. The game hung on that 22-22 knife-edge for 19 minutes, when Field's foul on O'Loughlin handed Danny Tickle the chance to kick Wigan ahead for the first time.

But for Millward, and Wigan's chairman Maurice Lindsay and owner Dave Whelan, who were sitting one row in front of him in the stand, there were more agonising moments to endure as Semi Tadulala crossed in the corner for Wakefield, only for Kirkpatrick to rule Jamie Rooney's pass forward.

Wigan finally secured their win with the scruffiest try imaginable, as two Moran kicks bounced kindly off Wakefield players for David Vaealiki to stretch over on the left, a sign perhaps of a change in the wretched luck that has followed the club this season. Tickle converted, then Pat Richards added a penalty as the loyal hardcore of Wigan's supporters danced in the rain on the uncovered terrace at the Doncaster Road end.

"I'm happy for the players, I'm happy for the supporters, I'm just happy to be in the next round," added Millward, who is surely due a little more luck in tomorrow night's fifth-round draw. Meanwhile, in the dressing room, his players were starting another chorus.